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排序方式: 共有579条查询结果,搜索用时 171 毫秒
1.
神经生长因子对小鼠突触体内Ca^2+水平的调节作用 总被引:4,自引:1,他引:3
观察了多次海马内微注射NGF对小鼠突触体内游离钙水平的影响,并在离体情况下观察NGF对EGTA和CaCl2分别造成突触体内低钙和高钙状态的调节作用。结果如下:(1)在体实验表明,一定剂量的NGF可显著降低老年小鼠海马突触体内游离钙水平(P<005);(2)离体实验表明,当突触体游离钙水平降低时,适当剂量的NGF具有升高游离钙水平的作用;而突触体内游离钙水平升高时,则NGF有降低游离钙水平的作用。提示NGF对游离钙水平的双向调节作用可能是NGF改善老年性记忆衰退的作用机制。 相似文献
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MY Mancao LJ Sindel PH Richardson FM Silver 《Acta paediatrica (Oslo, Norway : 1992)》1996,85(1):118-120
Croup is an acute infectious illness usually occurring in children; it is characterized by brassy cough and stridor. The main pathogens include mainly parainfluenza and influenza viruses. Recently there have been reports of prolonged croup caused by the herpes simplex viruses. We report two cases of prolonged croup due to herpes simplex types 1 and 2. We also review and summarize the reported pediatric cases of herpetic croup. 相似文献
4.
Duncan WC; Illingworth PJ; Young FM; Fraser HM 《Human reproduction (Oxford, England)》1998,13(9):2532-2540
The molecular mechanisms involved in luteolysis are still unclear in the
primate. This study aimed to investigate the effect of induced luteolysis
on the ovarian luteinizing hormone (LH) receptor and the steroidogenic
enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset
monkey. Luteolysis was induced in the mid-luteal phase either directly by
systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal
using systemic gonadotrophin releasing hormone antagonist (GnRHant)
treatment. The LH receptor was studied by isotopic mRNA in-situ
hybridization and in-situ ligand binding and 3beta-HSD expression was
studied using isotopic mRNA in-situ hybridization and immunohistochemistry.
Induced luteolysis was associated with a reduction in the expression of LH
receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a
reduction in the LH receptor (P < 0.05) and 3beta-HSD protein
concentrations within 24 h. There were no differences in the findings
whether luteolysis was induced with PGF2alpha or GnRHant. This study shows
that disparate mechanisms to induce luteolysis in the primate result in an
identical rapid loss of the LH receptor and 3beta-HSD. In conclusion,
induced luteolysis leads to rapid loss of the steroidogenic pathway in
luteal cells.
相似文献
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Reconstitution of CD4+ T cell responses in HIV-1 infected individuals initiating highly active antiretroviral therapy (HAART) is associated with renewed interleukin-2 production and responsiveness 下载免费PDF全文
Hardy GA Imami N Sullivan AK Pires A Burton CT Nelson MR Gazzard BG Gotch FM 《Clinical and experimental immunology》2003,134(1):98-106
Reconstitution of functional CD4(+) T cell responsiveness to in vitro stimuli is associated with continuous highly active antiretroviral therapy (HAART). Thirty-six antiretroviral naive patients received HAART over 16 weeks. Antigen-specific, mitogen and interleukin (IL)-2 induced lymphocyte proliferative responses and specific IL-2 and IL-4 production were assessed at each time-point, together with quantification of HIV-1 RNA load and lymphocyte populations. Reconstitution of recall responses was limited largely to persistent antigens such as Herpes simplex virus and Candida, rather than to HIV-1 or neo-antigens. Recall antigens, mitogens and IL-2-induced renewed responses were associated with in-vitro production of IL-2, but not IL-4. Differential responsiveness to low versus high concentration IL-2 stimulus increases in a stepwise manner, suggesting normalization of IL-2 receptor expression and improved functionality. These increases in in-vitro proliferative responses thus probably reflect short lived effector clones, driven by ongoing antigenic stimulus associated with persisting long-term organisms. In this context non-responsiveness to HIV-1 antigens suggests ongoing HIV-1 specific clonal T cell anergy. 相似文献
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Transition metal complexes containing vanadium IV have been shown to
modulate the cellular redox potential and catalyse the generation of
reactive oxygen intermediates (ROI). Since sperm function is exquisitely
susceptible to ROI, we examined the effects of stable chelate complexes of
vanadocenes on human sperm motility. We synthesized seven structurally
distinct chelate complexes of bis(cyclopentadienyl)vanadium(IV) with
bidentate ligands [i.e. vanadocene acetylacetonato monotriflate (VDacac),
vanadocene hexafluoro acetylacetonato monotriflate (VDHfacac), vanadocene
N-phenyl benzohydroxamato monotriflate (VDPH), vanadocene acethydroxamato
monotriflate (VDH), vanadocene catecholate (VDCAT), vanadocene bipyridino
ditriflate (VDBPY), and vanadocene dithiocarbamate monotriflate (VDDTC)],
and evaluated their spermicidal activity using computer-assisted sperm
analysis (CASA; Hamilton-Thorne). All seven chelate complexes of vanadocene
elicited potent spermicidal activity at micromolar concentrations (EC50
values: 3.9-106 microM) without affecting the sperm acrosome integrity. The
catecholate and acetylacetonate complexes of vanadocene were the most
active and the bipyridyl complex the least active with an order of efficacy
VDCAT > VDacac > VDDTC > VDPH > VDH > VDHfacac > VDBPY.
The spermicidal activity of chelate complexes of vanadocenes was rapid and
irreversible since the treated spermatozoa underwent apoptosis, as
determined by the flow cytometric analysis of mitochondrial membrane
potential, surface annexin V binding assay, in-situ nick-end labelling of
sperm nuclei, and confocal laser scanning microscopy. These results provide
unprecedented evidence that chelate complexes of vanadocene with bidentate
ligands have spermicidal and apoptosis inducing properties. These
vanadocene complexes, especially VDacac, may be useful as contraceptive
agents.
相似文献
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